I need to completely cover a tattoo, but have no supplies!?

I need to cover a tattoo. For a date, we are going swimming. I don't have much supplies. What can I use around the hous to hide it AND it be water proof. I do have a cheep liquid foundation(see through), acrylic paint(I know thats water proof), and thats about it. IS THERE ANYTHING ELSE I CAN USE!!!!????? HELP!